Window balancing device



'Jan. 2, 1934. w. YOUNG WINDOW BALANCING DEVICE Filed Sept. 12, 1932 Patented Jan. 2, 1934 UNITED STATES PATENT OFFICE WINDOW BALANCING DEVICE William Young, Wishaw, Scotland Application September 12, 1932, Serial 632,828, and in Great Britain September 2-5,

3 Claims.

My invention relates to a balancing device suitable for all types of mechanically operated balanced windows, and other like contrivances.

According to this invention, I provide a thread on a shaft with a suitable angle on which a nut is freely carried, against the nut is a compression spring with suitable adjustment to carry varying weights. It will be observed that, as the shaft is turned, the nut moves along the thread, and increases the spring pressure, and, immediately on releasing the shaft, the re-action of the spring pressure would at once act on the nut and rotate the shaft back to its normal position. On the shaft pulleys or rollers can be arranged for carrying cables, or such like, which would, in turn support a window or like contrivance.

As the above-mentioned device would make the carrying capacity of the cables on the pulleys or rollers greater when the spring pressure is at its maximum, which in many cases is not advisable, as a constant pressure is required, this can be prevented by making the screw in the form of a scroll or spiral with the thread, or such like, arranged with a varying pitch.

In this form of the invention a groove of a varying pitch is cut on the shaft, and a sleeve having a ball therein to ride in the groove is engaged externally by a compression spring. By doing so, as the spring pressure increases, the angle of the scroll pitch decreases, the variation of the scroll pitch, or angle, being arranged to compensate for the increased pressure on the spring, as the nut or sleeve moves along the shaft, thereby making the lifting capacity on the cable constant or otherwise in its travel.

In order that my invention may be properly understood and readily carried into effect, I have hereunto appended one sheet of drawings of which:

Figure l is an end elevation of part of a window illustrating my invention with the balance shown in the top position and supporting the window or like contrivance.

Figure 2 is a front sectional view of Figure 1.

. Figure 3 is a front sectional view of a slight 5 suitably fixed to the top of the window F. The

' shaft B is suitably threaded or screwed and has mounted thereon a nut G. One end of a spring H bears against the end of nut G, and the other end bears against an adjusting screw J. An adjusting nut K is threaded to the adjusting screw J and is provided with holes L for turning same when the pressure of the spring has to be altered. The whole is enclosed in a suitable casing M and the shafts A and B are supported centrally in the casing by the bearings N. 7

Referring to Figure 3 of the drawing, which shows a variable threaded shaft M, the pitch of the thread or spiral decreasing so that, when the window is being lowered, the extra compression of the spring I-I caused by the nut or sleeve 0 moving along the shaft is compensated by the gradually reduced pitch of the scroll or spiral so that the resultant pressure on the shaft between the spring and the angle of the thread or spiral remains constant (or otherwise if desired) throughout the travel of the window or such like contrivance. The nut in this case consists of a sleeve 0 having a ball P which engages with the groove or thread on the shaft M. The shaft M and the shaft A are connected together adjacent their inner end portions by a sleeve C through which pins or other fastening means are passed. The screw K is supported on the shaft M and is provided with an enlarged head portion at one end to abut against the bearing or support N. The other end of the screw K is externally screw threaded to receive the internally screw threaded nut J When it is desired to change the tension on the spring H for varying weights in sashes, the screw K may be manually rotated to move the nut J in a longitudinal direction inside the casing M.

For a cable, as above described, supporting a window, or such like, it is found that a suitable diameter of pulley or roller is necessary to carry the cables, and, in most cases, it requires a considerable amount of space for suitable operation, and, as one of the main features, particularly in windows, is reducing the size of the balance-gear, to the smallest possible limit, instead of the cable, as at present generally in use, I propose that very thin bands of stainless steel or other suitable material be utilized, and, owing to the thinness of the metal of which the band is formed, I am enabled to use a drum of small diameter. It will also be seen that, for a specified .1 travel, the thinness of the band makes the effec tive diameter of the drum very little reduced when the cable has travelled a considerable distance in its extended position.

It is of course understood that the balance balanced Windows having a frame with a sash slidable therein comprising a casing, a shaft housed in said casing and having a spiral runway, a movable member mounted on said shaft, an adjustable nut supported on said shaft in spaced relation to said movable member, a spring housed in the casing between said movable member and said nut, rotatable members housed in said casing and supported on said shaft, and strips for engaging the rotatable members with the shaft whereby the movement of the sash operates the movable member mounted on the shaft to compress the spring and counterbalance the weight of the sash.

2. A balancing device for mechanically operated balanced Windows having a, frame with a sash slidable therein comprising a casing, a shaft having a spirally cut runway to a varying pitch, a sleeve mounted on the shaft, a ball carried by said sleeve to enter said runway to permit movement of said sleeve on said shaft, an adjustable spring housed in said casing to engage said sleeve, and means for connecting the shaft with the sash whereby movement of the sash operates the sleeve to compress the spring and counterbalance the weight of the sash.

3. A balancing device for mechanically operated balanced Windows having a frame with a sash slidable therein comprising a casing fixed in the frame, a shaft rotatably mounted in said casing and having a spirally cut groove to a varying pitch, a sleeve mounted on the shaft, a ball carried by the sleeve to enter the groove to permit sliding movement of the sleeve upon the shaft, an adjustable nut mounted on the shaft and spaced from said sleeve, a spring housed between the sleeve and the nut, rollers supported on the shaft to rotate therewith, and means for connecting the rollers and the sash whereby the movement of the sash operates the spring to counterbalance the weight of the sash.

, WILLIAM YOUNG. 

